Mark Memmott

Survivors are telling harrowing tales about what happened Monday morning at Oikos University in Oakland when a man who police say once attended the small Christian school allegedly ordered the dozen or so people in a classroom to line up against a wall, drew a handgun and started firing.

Reporting that it has had the video "clarified" by a forensics company, ABC News is now saying that a police surveillance recording of George Zimmerman "shows the neighborhood watch captain with an injury to the back of his head."

Two "powerhouse" programs — Kansas and Kentucky.

Rosters full of potential NBA stars.

All the hype you would expect from an NCAA men's basketball championship.

But, alas, don't be surprised if there aren't as many "silky smooth jumpers" and other great shots as you might expect during tonight's big game, NPR's Mike Pesca reports.

Three things are working against the teams:

"It's constitutional," President Obama declared this afternoon when asked about the 2010 health care overhaul legislation that was the subject of three days' worth of Supreme Court hearings last week.

He's confident a majority of the justices will agree, Obama added. Many Supreme Court watchers are less certain.

The president make those comments in response to a question that came up during a joint news conference at the White House with Canadian Prime Minister Stephen Harper and Mexican President Felipe Calderon.

The morning TV air wars get serious again Tuesday with former Alaska Gov. Sarah Palin's guest host slot on NBC's The Today Show — opposite former CBS Evening News' anchor Katie Couric's guest slot on ABC's Good Morning America.

In the lead-in to the faceoff, there was some fun on Today today.

During a phone call with Palin, host Matt Lauer wondered "what are you doing to prepare? Are you reading some newspapers?"

The activist group behind the "Kony 2012" movement and Web video that went viral in March says it will release "Kony 2012, Part II" on Tuesday.

There was a 1.1 percent decline in spending on construction in February vs. January, the Census Bureau just reported. But spending was still 5.8 percent above the level of February 2011.

According to the bureau, spending on home construction was unchanged in February from the month before. Public construction spending was down 1.7 percent.

Good morning.

Our early headlines:

-- Trayvon Martin Case: Voice Calling For Help Isn't Zimmerman's, Experts Say.

-- Mega Millions Mystery: Who Won?

"A Pakistani court on Monday convicted Osama bin Laden's three widows and two of his grown-up daughters of illegal residency, sentencing them to 45 days detention and ordering their deportation," Pakistan's Dawn newspaper reports.

The wait continues to see who bought the three winning tickets in Friday's record $656 million Mega Millions lottery drawing.

If for some reason you haven't checked yet (yeah, right!) the winning numbers were 2, 4, 23, 38, 46 and the mega ball was 23.

Over the weekend, The Orlando Sentinel reported that two experts it consulted believe the voice heard calling for help in the background during a 911 call to police is not that of George Zimmerman, the neighborhood watch volunteer who says he acted in self defense when he shot and killed Trayvon Martin on Feb. 26 in Sanford, Fla.

In Wisconsin, "state elections officials ordered a set of historic recall elections Friday, making [Republican] Scott Walker the third governor in the nation to face a recall and Rebecca Kleefisch [R] the first lieutenant governor to face one," Milwaukee's Journal Sentinel reports.

During nine years on the run in Pakistan, Osama bin Laden used at least five safe houses and fathered four children, the youngest of his three wives has told Pakistani investigators, according to The New York Times.

Amal Ahmad Abdul Fateh, now 30, married bin Laden in 2000.

"There would have been George dead had he not acted decisively and instantaneously in that moment when he was being disarmed," the brother of George Zimmerman told CNN's Piers Morgan last night in one of the most extensive interviews yet with someone from the family of the man who shot and killed Florida teenager Trayvon Martin on Feb. 26.

There was a 0.8 percent rise in personal spending in February from January, the Bureau of Economic Analysis just reported. It was the strongest gain in seven months, according to The Associated Press.

But personal income rose just 0.2 percent, the bureau adds. And "disposable personal income," what's left after personal taxes, also rose only 0.2 percent.